首先在WEB配置页面中添加tld文件
其次，然后再WEB.XML文件中配置说明
<!-- 添加自定义JSP标签 -->
<jsp-config>
<!-- 在JSP页面中同样也需要引用标签，这里只是获取的uri定义结果不一样 -->
<taglib>
<taglib-uri>/hb</taglib-uri>
<taglib-location>/WEB-INF/taglibs/c.tld</taglib-location>
</taglib>
<taglib>
<taglib-uri>/fmt</taglib-uri>
<taglib-location>/WEB-INF/taglibs/fmt.tld</taglib-location>
</taglib>
<taglib>
<taglib-uri>/functions</taglib-uri>
<taglib-location>/WEB-INF/taglibs/fn.tld</taglib-location>
</taglib>
</jsp-config>
最后，页面展示
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="/hb"%>
<%@ taglib prefix="fmt" uri="/fmt"%>
<%@ taglib prefix="fn" uri="/functions"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'fn.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
使用fn功能是对集合长度的取值<p></p>
<%
ArrayList arrayList1 = new ArrayList();
arrayList1.add("aa");
arrayList1.add("bb");
arrayList1.add("cc");
request.getSession().setAttribute("arrayList1",arrayList1);
%>
${fn:length(sessionScope.arrayList1) }
<hr/>
fn:contains函数用来判断源字符串是否包含子字符串<br/>
${fn:contains("ABC","a") }<br/>
${fn:contains("ABC","A") }
<hr/>
fn:containsIgnoreCase跟fn:contains函数差不多，唯一的区别是不区分大小写
<br/>
${fn:containsIgnoreCase("ABC","a") }<br/>
${fn:containsIgnoreCase("ABC","A") }
<hr/>
fn:startsWith函数用来判断源字符串是否符合一连串的特定词头(区分大小写)<br/>
${fn:startsWith("ABC","ab") }<br/>
${fn:startsWith("ABC","AB") }
<hr/>
fn:endsWith函数用来判断源字符串是否符合一连串特定词尾（区分大小写）<br>
${fn:endsWith("ABC","bc") }<br/>
${fn:endsWith("ABC","BC") }
<hr/>
fn:indexOf函数用于取得子字符串与源字符串匹配的开始位置，如果没有匹配的将返回-1<br/>
${fn:indexOf("ABCD","BC") }<br/>
${fn:indexOf("ABCD","aBC") }
<hr/>
fn:join函数允许为一个字符串数组中的每个字符串加上分隔符连接起来<br>
<%
String[] stringArray={"huang","biao","dage"};
request.setAttribute("stringArray",stringArray);
%>
${stringArray }<br/>
${fn:join(stringArray,"-") }
<hr/>
fn:replace函数允许为源字符串做替换工作<br/>
${fn:replace("ABC","A","#") }
<hr/>
fn:split函数用于将一组由分隔符分隔的字符串转换为字符串数组<br/>
${fn:split("a,b,c",",") }
<hr/>
fn:trim函数将删除源字符串中结尾部分的“空格”以产生新的字符串<br/>
${fn:trim("abc ") }d<br>
<hr/>
fn:toUpperCase函数允许将源字符串中的字符全部转换为大写字母<br>
${fn:toUpperCase("abcd") }
<hr/>
fn:toLowerCase函数允许将源字符串中的字符全部转换成小写字母<br/>
${fn:toLowerCase("ABCD") }
<HR/>
fn:substringBefore函数允许截取源字符串从开始到某个字符串<br/>
${fn:substringBefore("ABCD","BC") }
<hr/>
fn:substringAfter函数允许截取源字符串结尾的后一个字符<br/>
${fn:substringAfter("ABCD","BC") }
<hr/>
fn:substring函数用于截取字符串<br/>
${fn:substring("ABC",1,2) }
<hr/>
</body>
</html>
备注：上面的配置信息不是必须的，只是为了学习使用
